Mick McCarthy is keeping his fingers crossed that the knee injury which forced Gary Breen off after 29 minutes against Coventry on Saturday will not be serious.

The defender spent yesterday being assessed by Sunderland's medical staff and McCarthy is hoping for welcome news this morning.

He said: "Gary got a bang on the knee. He thought he would be able to continue but when he stood up and tried to run, he could tell it wasn't right. It will be assessed. I will not know whether the problem is serious until we have been through that process."

Breen has established himself as a key player since arriving at the Stadium of Light this summer and, should he face a spell on the sidelines, it would prove a major blow to McCarthy.

Joachim Bj&#xF6;rklund replaced the Republic of Ireland international on Saturday but doubts remain over the Swede's ability to stay free of injury.

With this weekend's clash with Wigan having been postponed, the Wearsiders are next in action at Crewe on November 22. McCarthy will hope that the break will give Breen the time he needs to recover.

Meanwhile, McCarthy has urged fans to be patient with Stewart Downing after his home debut on Saturday. The on-loan Middlesbrough winger impressed during his first two appearances but struggled against Coventry.

"He has been brilliant but I think he found three games in seven days a bit taxing," said McCarthy. "He has been used to playing reserve football once a week."